Dedicated to all those who served with or supported the 456th Fighter Squadron or 456th Fighter Interceptor Squadron or the UNITED STATES AIR FORCE

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The Convair X-11 & X-12

The Convair X-11

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The Convair X-11 Being Launched

The
Convair X-11 (originally designated the Convair XSM-16A)
was the first testbed for what became the
Atlas missile program. Later the
Convair X-12 became the second, more advanced testbed for the Atlas
program.

Service History

A total of 12 X-11's were built and tested. The first three were involved
in static tests only. X-11 Number 4 and 6, were destroyed in launch
accidents. All others performed successful test flights. The test series
began on June
11, 1957
and ended on
June 3, 1958.

Specifications

General characteristics

Crew: Unmanned

Length: 96 ft (29.3 m)

Wingspan: 12 ft (3.66 m)

Height: ()

Empty weight: 12,500 lb (5,670 kg)

Loaded weight: 80,000 lb (36,300 kg)

Powerplant: 1×
rocket engine

Performance

Maximum speed: Mach 10+

Range: 600 nm (690 mi, 1,110 km)

Service ceiling: 40 mi (60 km)

(More Below)

Wikipedia

The Convair X-12

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The Convair X-12 being launched

The Convair X-12 was the second, more advanced testbed for the Atlas
rocket program. It was designed with 3 engines, its predecessor the Convair
X-11 used only one engine. It was powered by a 1.5 stage liquid-fuel rocket.
Its first flight was in July, 1958.

Service History

The X-12 pioneered the use of 1.5 stage rocket engines that became a
hallmark of the Atlas rocket program. It was also the first rocket to achieve
a flight distance that could be considered intercontinental when it flew 6,325
miles (10,179 km).

According to a 2001 article in Code One Magazine by Lockheed, no X-12 was
ever built or flown, altough imagery (at right) seem to contradict that.

Performance

Wikipedia,

Convair B-65/SM-65/CGM-16/HGM-16Atlas

The Atlas was the first Intercontinental Ballistic Missile (ICBM)
deployed by the USA. Its descendents are still in use today as civilian and
military space launch vehicles.

The Atlas development can be traced back to the days immediately
after World War II, when captured German rocket and missile technology
supported many new missile research studies. In April 1946, Consolidated-Vultee
(later Convair) began project MX-774 to study long-range ballistic
missiles. The studies led to the RTV-A-2
Hiroc test rocket, which tested several new design techniques which
would later be used in the Atlas. These features included a gimballed
nozzle, using the fuselage itself as fuel tank, and a separable nose cone.
Altough MX-774 was cancelled in June 1947, Convair was allowed to complete
three RTV-A-2 vehicles, and the first of these flew in July 1948. All three
flights were only partially successful but helped a lot to validate the new
design concepts.

After the cancellation of MX-774, Convair continued low-key internal
studies on ballistic missiles, developing the idea of the "one and one half"
stage rocket. In this type of design, both booster and sustainer engine(s)
would ignite at lift-off, and the boosters would be dropped later in the
flight. This circumvented the difficulty of having to ignite the sustainer at
high altitude, which was then considered a potential problem. When military
funding sharply increased after outbreak of the Korean War, Convair was
awarded a contract for the long-range ballistic missile project MX-1593
in January 1951. Later in 1951, the USAF decided to assign aircraft-like
designations to its guided missiles, and the designation B-65 was
assigned to the MX-1593 missile (named Atlas by this time).

In 1953 Convair had completed the initial design studies. One radically new
feature was the internal pressure stabilized flight structure. The missile's
skin was very thin, and was inflated by internal pressure like a balloon. This
significantly reduced the empty weight of the vehicle. However, it also made
the missile rather fragile, because a single hole in the skin would lead to
the collapse of the whole structure, just like a limp balloon. The initial
Atlas design was a huge 27 m (90 ft) long, 3.6 m (12 ft) wide rocket, with
five engines producing 2700+ kN (600000+ lb) of total thrust. The size was
deemed necessary to launch the expected very heavy (65 ton) thermonuclear
warhead to intercontinental range. Because of the limited accuracy of then
available intercontinental guidance systems, a megaton-class thermonuclear
warhead was necessary for the Atlas to be effective against hardened
targets. A ten-year development program was approved, with an initial
operational deployment planned for 1963. To minimize risk, it was decided to
develop a single-engine test vehicle first, designated X-11, followed
by a three-engine X-12 test vehicle and an XB-65 five-engine
strategic missile prototype.

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XB-65

In 1954, the H-bomb tests in the Pacific showed that the warhead for the
Atlas could be made significantly smaller and lighter than expected.
Therefore, the five-engine XB-65 design was cancelled and replaced by a much
smaller three-engine design. The booster engines were North American (Rocketdyne)
LR89, and the sustainer engine was a Rocketdyne LR105 enigne, both fueled with
RP-1 (kerosene) and liquid oxygen. Two small Rocketdyne LR101 vernier engines
were used for fine-tuning thrust and directional control. The whole Atlas
propulsion system was known as MA-2. In 1955, in the light of discovering
Russian ICBM activities, the Atlas development was accelerated, and it
was approved to flight test preliminary prototype models which lacked some
feartures of the planned production missile. The XB-65A Atlas A
had only booster engines, and a dummy warhead. In August 1955, the USAF
dropped all aircraft-like designations for guided missiles, and the Atlas
became the SM-65.

On 11 June 1957 the first attempt to fly an XSM-65A was made, but
due to a booster malfunction the missile had to be destroyed a few seconds
after lift-off. The first successful Atlas A flight to the full range
of 1100 km (600 nm) was the third one, on 17 December 1957. When Atlas A
testing was completed in June 1958, flight tests continued with the XSM-65B
Atlas B until December 1958. The XSM-65B tested all subsystems of the
Atlas, including the full three-engine propulsion system. A maximum
range of 10200 km (5500 nm) was reached. The XSM-65C Atlas C,
flown between December 1958 and August 1959, tested the thin-skinned fuel
tanks and the radio-command guidance in production configuration.

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XSM-65B

In July 1959, the XSM-65D prototype of the initial production
variant, the Atlas D, first flew. On 31 October 1959, the first U.S.
Air Force ICBM squadron went on Combat Alert at Vandenberg AFB, with 3
SM-65D missiles on unprotected open launch pads. To give the Atlas
at least some sort of protection, the follow-on bases were equipped with
"coffins" to store the missiles. This coffin was a blast-protected building in
which the Atlas was stored horizontally. Following the launch order,
the roof of the coffin would slide away, the missile raised to the vertical,
ready for fueling and launching. The Atlas ICBM had several significant
operational shortcomings. It had to be fueled immediately before launch,
leading to a high reaction time (about 15 minutes) after launch order. The
fueling was also a very dangerous process which lead to several heavy
explosions during operational tests. The radio-command/inertial guidance
system of the Atlas D was susceptible to jamming and restricted the
launch frequency of an Atlas D squadron to one missile every 5 minutes.
The SM-65D used either Mk.2 or Mk.3 blunt reentry vehicles. There was also an
unarmed training version of the SM-65D, designated USM-65D.

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The SM-65E Atlas E was an improved SM-65D. It used a more
accurate Mk.4 reentry vehicle, had an improved propulsion system (designated
MA-3), and used an all-inertial guidance system developed by Bosch Arma, which
was originally planned for the HGM-25A Titan
I. With this navigation system, located in the distinctive large bulge
on the side of the missile, the Atlas E could reach an accuracy of
about 600 m (2000 ft) CEP. Component testing on modified Atlas D
missiles began in March 1960, and in February 1961 the first full Atlas E
flight occurred. The SM-65E became operational in September 1961. Because the
all-inertial guidance system did away with the necessity to launch the missile
close to the launch control center of the base, the Atlas E was
deployed in widely dispersed patterns. Adding also new semi-buried coffins,
the Atlas E was significantly better (but still not satisfactorily)
protected against a preemptive strike than the D model. The USM-65E was
the unarmed training version of the Atlas E.

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SM-65E (CGM-16E)

SM-65F (HGM-16F

Because even the dispersed storage and semi-buried coffins of the Atlas
E offered insufficient protection, the USAF decided already in 1959 to
deploy Atlas missiles in underground silos, just like the HGM-25A Titan
I. This resulted in the SM-65F Atlas F missile, which
was essentially an SM-65E with a modified fueling system to accomodate the new
silo launcher. The first silo-stored Atlas F squadron became
operational in November 1962. Because the SM-65F could be fueled while still
in the silo, launch survivability was much improved. After fueling, it took
only two minutes to raise and launch the missile. In a crisis, it was even
possible to store the SM-65F fully fueled in the silo for some length of time,
which lead to a reaction time of only five minutes. However, fueling in the
silo was even more dangerous than in the open, and four Atlas Fs
violently exploded during this operation, destroying their silos.

In June 1963, the existing Atlas missiles were re-designted in the
xGM-16 series as follows:

Old Designation

New Designation

SM-65D

CGM-16D

USM-65D

CTM-16D

SM-65E

CGM-16E

USM-65E

CTM-16E

SM-65F

HGM-16F

There are also sources which claim that the SM-65Ds based on unprotected
pads at Vandenberg AFB were re-designated as PGM-16D. While this would
be logical, the PGM-16D designation was apparently never officially allocated.
Also, reports claiming that XPGM-16A, XPGM-16B, and XPGM-16C
were the new designations for XSM-65A, XSM-65B, and XSM-65C, respectively, are
in error, because all three development models had long been expended by 1963.
While the 1963 redesignations did include some "paper" designations of retired
or cancelled missiles, this was not true for the Atlas series.

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Atlas family (D is shown with Mk.4 RV of E/F)

After the
LGM-30 Minuteman had become operational in early 1963, the Atlas
became rapidly obsolete. By October 1964, all Atlas D missiles had been
phased out, followed by the Atlas E/F in April 1965. About 350 Atlas
ICBMs of all versions were built, with a peak deployment level of 129 (30 D,
27 E, 72 F).

The Atlas was used as a space launch vehicle since the very
beginning of the program, and Atlas developments are still used in this
role in the 21st century. Converted ICBMs and early purpose-built space
launchers, usually with additional upper stages, were used by the USAF under
the basic SLV-3 designator. In 1990, the Atlas E, Atlas II
and Atlas IIA/AS vehicles received the official military designations SB-1A, SB-2A and SB-2B, respectively. For details on
Atlas launch vehicles, see page on
SLV-3/SB-1/SB-2. Current prime contractor for all Atlas rockets is
Lockheed Martin.

Note: Data given by several sources show slight variations. Figures
given below may therefore be inaccurate!